“…Ag nanoparticles synthesized by chemical approach do not exhibit peak in the infra-red region. No appearance of any absorption peak for Ag confirms the synthesis of metallic silver only in this approach, without the formation of oxides of silver (Beura et al 2021). The broad absorption band at 3225cm -1 corresponds to the presence of hydroxyl group.…”
In this study, silver-nickel oxide/ calcium alginate (Ag@NiO/Alg) hydrogel beads were synthesized. The preparation of Ag@NiO was carried out in two steps: 1) synthesizing the nickel oxide nanoparticle through precipitation method, and 2) adhering of the Ag + ion from silver nitrate solution and reduction with sodium borohydride. The nanomaterial was mixed with alginate biopolymer aqueous solution and extruded through syringe in a dropwise manner into a CaCl2 aqueous solution for inotropic crosslinking. Through this method, Ag@NiO/Alg beads were formed which were characterized by different instrumental techniques. The catalytic efficiency of Ag@NiO/Alg was evaluated for the reduction of rhodamine B (RhB) and methyl orange (MO), in the presence of sodium borohydride reducing agent. The uncatalyzed RhB and MO reduction reactions did not show a significant decrease in the absorbance value at λmax within the given experimental time. It was due to the large kinetic barrier. A small decrease in the absorbance value for uncatalyzed reaction in the presence of very high concentration of 3 reducing agent was observed, indicating that the reactions are thermodynamically feasible. After applying various kinetic order equations to the experimental data, the reactions were found to follow pseudo-first order kinetics using the Ag@NiO/Alg catalyst. The apparent rate constants (kapp) were determined as 0.33358 min -1 and 0.20882 min -1 for catalytic reduction of RhB and MO, respectively. Furthermore, reduction reactions were studied at varying dye concentration and catalyst dosages. The recovered catalyst was reused up to five cycles without significant drop in the activity.
“…Ag nanoparticles synthesized by chemical approach do not exhibit peak in the infra-red region. No appearance of any absorption peak for Ag confirms the synthesis of metallic silver only in this approach, without the formation of oxides of silver (Beura et al 2021). The broad absorption band at 3225cm -1 corresponds to the presence of hydroxyl group.…”
In this study, silver-nickel oxide/ calcium alginate (Ag@NiO/Alg) hydrogel beads were synthesized. The preparation of Ag@NiO was carried out in two steps: 1) synthesizing the nickel oxide nanoparticle through precipitation method, and 2) adhering of the Ag + ion from silver nitrate solution and reduction with sodium borohydride. The nanomaterial was mixed with alginate biopolymer aqueous solution and extruded through syringe in a dropwise manner into a CaCl2 aqueous solution for inotropic crosslinking. Through this method, Ag@NiO/Alg beads were formed which were characterized by different instrumental techniques. The catalytic efficiency of Ag@NiO/Alg was evaluated for the reduction of rhodamine B (RhB) and methyl orange (MO), in the presence of sodium borohydride reducing agent. The uncatalyzed RhB and MO reduction reactions did not show a significant decrease in the absorbance value at λmax within the given experimental time. It was due to the large kinetic barrier. A small decrease in the absorbance value for uncatalyzed reaction in the presence of very high concentration of 3 reducing agent was observed, indicating that the reactions are thermodynamically feasible. After applying various kinetic order equations to the experimental data, the reactions were found to follow pseudo-first order kinetics using the Ag@NiO/Alg catalyst. The apparent rate constants (kapp) were determined as 0.33358 min -1 and 0.20882 min -1 for catalytic reduction of RhB and MO, respectively. Furthermore, reduction reactions were studied at varying dye concentration and catalyst dosages. The recovered catalyst was reused up to five cycles without significant drop in the activity.
“…The stretching vibrations of C–O were blamed for the band at 1073 cm −1 . The transmittance peak at 486 cm −1 is also attributed to Zn–O vibration (Beura et al 2021 ). Fig.…”
In this study, we are reporting biogenic synthesis of silver nanoparticles and hydrothermal synthesis of zinc oxide nanoparticles. Using convenient mechanical milling methods, nanocomposites with superior photocatalytic and catalytic properties are synthesized. Herein, we have adopted a green, eco-friendly, and economical route for the synthesis of Ag nanoparticles using Zingiber officinalae rhizome extract in an aqueous solution. The synthesized materials were characterized using UV–Vis spectroscopy, XRD, SEM & FE-SEM, FT-IR, Raman, and a particle size analyzer with zeta potential analysis. The photocatalytic activities of Ag, ZnO and their composites were studied by observing the degradation of methylene blue and crystal violet dyes under natural sunlight. Then the catalytic efficacies of synthesized nanoparticles for various organic transformation reactions were studied. Ag–ZnO nanocomposites were predicted to have improved photocatalytic activity and organic transformation reactions, allowing them to be used in environmental remediation applications.
“…The beneficial contribution of Ag to the photocatalytic properties of ZnO has been widely reported in the literature in recent years. An important part of these studies has focused on Ag decorated ZnO-based nanostructures due to their very advantageous surface-to-volume ratio in the photocatalysis process [26][27][28][29][30][31][32]. However, when the catalyst is in a nanopowder form, its separation from the treated water and its recovery for reuse become a major constraint.…”
Section: Introductionmentioning
confidence: 99%
“…Most often, authors using the sol-gel process combine Ag precursors (silver nitrate or silver acetate) with ZnO precursors, [26][27][28][29][30][31][32]35,36]. This can lead to a substitution effect of Ag + to Zn 2+ in the host lattice.…”
Section: Introductionmentioning
confidence: 99%
“…The ZnO-Ag system, as a catalyst, has been used to study the photocatalytic degradation of various dyes. Methylene blue [26,27,[30][31][32]36] and methyl orange [26,28,34] are the dyes that have been studied the most. To date, no study, to our knowledge, has been devoted to the degradation of indigo carmine (IC), one of the most widely used dyes and the most polluting components found in the textile industry [40], by this type of thin film photocatalyst.…”
We used a sol–gel spin coating technique to synthesize nanocomposite thin films based on zinc oxide (ZnO) loaded with silver nanoparticles (NPs). We tested these ZnO/Ag NP photocatalysts, with a thickness of about 100 nm, for the photodegradation of the indigo carmine dye solution. The study focused on the effects of Ag NPs on the ZnO matrix as well as the impact of their concentration on the photocatalytic performance of the nanocomposite. The study also highlighted the high stability of the photocatalytic performance of these nanocomposites. This work is a contribution in the search for non-toxic thin film photocatalysts that is usable under solar radiation for the treatment of contaminated wastewater. Innovation in the field of heterogeneous photocatalysis requires the use of solar resource with efficient results in terms of photocatalytic performance.
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